Detergent rubber compound and process of producing same



Patented Apr. 12, 1949 DETERGENT RUBBER COMPOUND AND PROCESS OF PRODUCING SAME William Romaine, In, San Mateo, Calif.

No Drawing. Application November 10, 1948,

Serial No. 59,407

12 Claims.

This invention relates to a rubber product which incorporates a detergent andrefers also to the process of producing such a product. The invention further refers to a cellular or spongelike structure formed of rubber incorporating a detergent. This application is a continuationin-part of my co-pending applications serial No. 748,670, filed May 16, 1947, and Serial No. 778,277, filed October 6, 1947.

It is the general object of the present invention to provide a rubber-like resilient and preferably spongy, porous retaining structure into which rubber-like structure is incorporated a soil removing detergent or surfaceactive compound which will be held in the product in a form which or otherwise migrate to the surface of the rubberlike spongy structure and thus become available for detergent action upon contact with water.

In accordance with the present invention, I incorporate substantial quantities of a soil removing, clean ing, surface acting detergent media into a rubber-like composition, which rubber-like composition I subsequently convert by a thermal reaction, chemical reaction or mechanical means into the form of a spongy porous intercommunicating or unitary cellular structure of comparatively large surface area.

In the product and in the process of the present invention there may be employed any soil removing, cleansing, surface acting detergent, by which I mean to include as useful in the present invention all such surface active agents as will modify the properties of the surface layer of an aqueous phase in contact with another oily phase. Such detergent materials generally will have present in the same molecule one or more hydrophilic or water attracting groups and one or more hydrophobic or water repelling groups, consisting of one or more hydrocarbon or alkyl groups having sub stantially straight-chain hydrocarbon radicals of the range, for example, of Ca to C 2, and having molecular weights between 250 and 500.

Generally the detergents useful in the present invention include sulfuric acid esters of fatty alcohols, sulfonapthenates, sulfosuccinic acid .esters, alkyl-aryl sulfonates, etc., or mixtures thereof. Metal salts of such compounds are likewise useful detergents. As to the sulfuric acid esters of fatty alcohols, they are alkyl sulphates useful as detergents. These may include, for example, a very large number of compounds derived by reaction of higher alcohols with'sulfuric acids, the alcohol group containing between 8 and 20 carbon atoms and preferably between will permit the detergent to bleed, blow, exude,

2 be handled by hands 12 and 18. Thus, most commonly, the alkyl sulphate detergents are derived from such alcohols as lauryl, myristyl, palmityl, and stearyl.

The alkyl aryl sulphonate types of detergent or wetting agent useful in the present invention are generally in 'the form of either an alkyl sulphonated benzene or toluene, the benzene compound being preferable, in which the alkyigroup is mostly of a straight hydrocarbon chain having from 8 to 20 carbon atoms and preferably about 12 to 15 carbon atoms. Generally such alkyl aryl sulphonate detergents will not be any specific compound, but will include a plurality of alkyl aryl sulphonates of the type described. The sulfonaphthenates similarly have alkyl groups, principally the straight hydrocarbon chains having from 8 to 20 carbon atoms, and preferably around 12 to 15 carbon atoms.

The selection of the detergent agent from this group of useful aterials inthe preparation of the product and the process of the present invention depends upon the particular use to which the "product is to be put. In the products to be used in cleaning windows, or where the product is to in operation. it is desirable that the detergent be selected with a view of minimizing the physiological effects. Moreover, while such detergents generally are useful in the process of the present invention, some thereof induce softening or a plasticizing effect on the product, permitting incorporation of less of such detergent in the useful product as compared with other preferred detergent materials.

In the product and process of the present invention the rubber and detergent are mixed together, together with vulcanizing constituents, and in certain cases constituents for other purposes. In order to produce a satisfactory product, it is necessary to secure adequate mixing, after which the product is either vulcanized, or blown first and then vulcanized.

The utility of the product and process of the present invention depend upon the incorporation of a large amount of detergent in the rubber. The product produced must retain a strong structure so that it may be handled in cleaning operations without disintegration. It is further generally highly desirable that the product be resistant to the action of oils and greases, since these materials are commonly encountered in cleaning operations. The preferred product and process of the present invention meets all of these requirements in that there is produced a product incorporating very high quantities of detergent, which spongy product has strong structural char- 3 acteristics and, moreover, is resistant to the action of oils and greases.

To produce such. a preferred product, the product and process of the present invention require utilization of proper rubber. If attempts are made to incorporate detergents into natural rub.- ber (Hecec brasiliensis) one is not able to utilize more than about ten parts of detergent per 100 parts of natural rubber, if the usual technique natural rubber is employed will havelower structural strength, so as to be of inferior quality as a cleansing article. Natural rubber products have the further disadvantage for detergent purposes in that natural rubber undergoes rapid deterioration and disintegration when in contact with oils and greases. l. have found,'however, that by utilization of certain synthetic rubbers in place of natural rubbers, it is possible to obtain satisfactory mixing on the usual rollers using as much as 80 parts of detergent per100 parts of synthetic rubber. Furthermore, products produced through the use of these synthetic rubbers are sponge products of high structural strength, well adapted for use as cleansing agents. Furthermore, the products. if correct synthetic rubbers are utilized, are highly resistant to deterioration or disintegration on contact with oils and greases.

Synthetic rubbers which may be utilized to obtain these desirable products include the butadiene-acrylonitrile type of synthetic rubbers, the polychloroprene synthetic rubbers, and the chloroprene-isoprene synthetic rubbers. All of the aforementioned synthetic rubbers allow the incorporation of high quantities of detergent (from to 80 parts of detergent per 100 parts of rubber) in the product, while at the same time producing sponge materials having strong structure and resistant to the action of oils and greases. The chloroprene-isoprene rubbers, at present, from a standpoint of expense only, do not, however, appear practical in the present invention. With any of such rubbers there may be admixed other less desirable rubber material, including natural rubber.

For less desirable products, other synthetic rubbers may be used. Thus, for example, I have found the use of butadiene-styrene type rubbers in the product and process of the present invention will permit ready mixing in the usual manner, and the incorporation of large quantities of detergent and the formation of a sponge product having high structural strength. The use of this type of rubber has only the objection that the product produced is subject to rapid deterioration and disintegration if brought into contact with oils and greases. Natural rubbers alone may be used in certain cases, but the use of natural rubber alone has many disadvantages.

When natural rubbers are compounded with detergents and the usual ingredients to effect vulcanization (sulfur accelerating and activating materials and the oxides and so-called blowing agents) the detergent acts to a considerable extent as a plastlcizing agent on the natural rubber and. moreover, in the case of some types of detergent esters, due to absorption of the available vulcanizing sulfur, or possibly change in the pH factors, the effectiveness of the vulcanization accelerators is retarded. I have also found that many types of detergent esters have a deteriorating effect upon natural rubber tending after varying periods of time to cause a reduction in strength and elasticity of the spongy porous structure.

Practically all of the ester type detergents have this softening effect to a more or less degree upon natural rubber. This action is apparent when as small as four parts detergent are combined with natural rubber and strongly present when the quantity as large as ten parts detergent are combined with natural rubber.

By the utilization of synthetic rubbers of the butadiene-acrylonitrile type, or the polychloroprene type, or the chloroprene-isoprene type, the softening or plastlcizing action of the detergent on the rubber is so relatively small that for certain purposes it becomes desirable in the product and process-of the present invention to deliberately include some platiclzing agent. Particularly where, under the present invention a soft sponge product is desired, it is my practice to either include along with the synthetic rubber a plastlcizing agent or else to mix with the synthetic rubber sufllcient of the natural rubber to act, in combination with the detergent added, as a plastlcizing agent on the synthetic material.

By incorporating into the product a limited quantity of the natural rubber a product is produced which has better wear resisting properties. Combinations or blends of both types of rubber, natural and synthetic, largely overcome the dimculties encountered when they-are used individually. The good points of one type neutralize, to considerable extent, the bad points of the other. After investigation of both types as individual materials, they were investigated as blends. The results were much more practical and serviceable. The softening or plastlcizing effect of ester detergents on natural rubber tended to satisfactorily reduce the nerve" or rigidity of the synthetic rubber. Likewise, the rigidity of the synthetic rubber tended to neutralize the excessive softening of the natural rubber by the action of the detergent, and thus a satisfactory and practical balance in that property is attainable. Further, much larger quantities of detergent may be incorporated into the blended rubber stocks, thus materially prolonging the serviceable life of v the finished device, without detracting from its necessary physical form and properties. The blended rubber stocks will also have much greater resistance to the deteriorating action of oils and greases with which it will come in contact in its ultimate intended use.

The amount or quantity of detergent that can be incorporated into the blended rubber stocks appears to be limited only by the amount that will cause failure to maintain the desired physical form and strength needed to permit proper functioning in its intended ultimate application. Because of the practically unlimited number of detergents that are possible, and their variable weight-volume ratios, it is impossible to predict encompassing quantity limitations in the amount of detergent that may be combined with the rubber phase.

The process and product of the present invention will be more completely understood from the following description of the-preferred examples of the invention. 1 r a In the first example of my invention the following materials were used in the following proportions by weight. I

In the foregoing formula the zinc oxide and stearic acid are activators; the benzothiazyl disulfide and tetra methul thiuram mono sulfide are vulcanizing accelerators, while sulfur is the vulcanizing agent.

. Any other or usual preferred type of vulcanizing activators or accelerators may be incorporated.

a The carbon black and the iron oxide are pigments added for the purpose of producing a dark prodnot and maybe omitted in'case a lighter colored product is desired. The sodium bicarbonate and 'diazoam ino benzene are blowing agents; that is, 4 materials utilized where a sponge" product is desired. If a more solid product isdesired, these Butadiene-acrylonitrile rubber 100.0 Zinc oxide,...-,-. 1 5.0 Ben'zothiazyldisulfide 2.0 Diphenylguanidine 1.0 Sulfur 1.5 Detergent 4----.. 50.0 Marter white 50.0 Carbon black 20.0

sulfate mono esters of high fatty alcohols. chiefly lauryl and myristyl derivatives. The plasticizer employed was what is known as Flexol 490 or a polyethylene glycol di-z-ethylhexoate. This material is utilized in the same manner; that is, ingredients mixed and kneaded together on rollers and finally blown and vulcanized into a sponge product: Z

As a further example of the present invention, wherea solid, nonporous or nonspongy product is desired. I'use-the following formula:

1 In this product I again use as a detergent the *Aquarex-D, although any of the class of detergents previously mentioned might be readily substituted therefor. After mixing the ingredients,

the product.

blowing agents may be omitted. AlsoI find that most detergents themselves function to'a limited ,extentas blowing agents when utilized in the process of the present invention. The detergent utilized in this process was Aerosol O. T., which is a dloctyl ester of sodium sulfosucclnic acid.

In this process of the present invention these materials are added to the rubber while the rubber is undergoing treatment on the usual rollers and the kneading action of the rollers continued until thorough mixing is I secured. Thereafter, .the

- mixed material is withdrawn from the rollers and.

placed in a suitable frame mold and heated. At the start of the heating operation carbon dioxide andother gases are generated within the material which have'the result of expanding the same into a porous. cellular or sponge structure in the vulcanization process during the final heating'period. As a result in' this example of the invention there is produced a sponge product dark in color'containing about 5.4 parts of detergent for 100 parts of rubber in the compound. The product'is use-' ful in cleaning operations; for example. in the cleaning of windows, automobile car bodies or other dirt surfaces. The product is utilized as a sponge exuding detergent during the cleaning process;

where'it is' desired to produce a sponge product,

I have used the following formula:

" In the foregoing formula the detergent employed: was .Aquarex-Di' which is sodium salts of Polychloroprene rubber 100.00 Extra light calcinedmagnesium oxide--- 4.00 Benzothiazyl disulfide' 0.50 Sodium acetate 0.50 Petrolatum 3.00 Softener '(for example di-2-ethylhexyl phthalate) 10.00/25.00 Detergent (for example Aquarex-D.) 10.00/50.00 Zinc oxide 5.00 Blowingagerit (for example di n itros'o I pentamethylene tetramine) '.50/2.00

1 As a'fur'therexample of the present invention;

the mixture is vulcanized under pressure into a solid sheet of material resembling substantially a rubber sheet at first appearance, but incorporating a substantially 'high quantity of detergent material which in use. particularlyin the presence or -water.-could be gradually-exuded from As a further e'xample'of the present invention, where it is desired toproduce asponge product,

1 have used the following formula;

As a further example of the present invention, where it is desirable to produce a sponge prod uct. but the requirements for oil and grease resistance are notneeded, I have used the following formula; t

Butadiene-styrene rubber j 100.00

Peptizing agent 2.00 Antioxidant (for exam'plepara-phe ylphenol) 1.00 Sulfur ;;e;; 3.00 Pet'rolatum 3.00 Accelerator (for example tetramethylthiuram-monosulfide) .50 vulcanization retarder (fox-example salicylic acid)y I 1.00

Detergent (for example Aquarex-D) 10.00/5 0.00

Softener (for exam-pie di-Z-ethyIheXyI Blowing agentease ofjbbtilfof fthje last two-examples. the ma'terial is utilized in the s'amefma'nnerfas l'in the previous: examples; that i the-in redients are mixed and kneaded together' on'jrollers. and

. V DI W fi d li i t nize in o sp hee'nrod- 'uctl The'jp'r'oduct -produced usingthepolychloro prene: type of rubber' is: excellent in all respects "and highly 'resistantto fragmentation, 'and also to deterioration and disintegration by contact with oils and greases. The product produced using the butadiene-styrene rubber'is' excellent in all respects except for the fact that it is subject to deterioration in contact with oils and greases.

. While in the foregoing examples specific detergents have been mentioned, the detergent used in each of theforegoing examples may be any of those previously classified. I have established, by test, that in each of the previous examples such detergents may be employed by the substitution of any of the class of detergents mentioned. Thus, in the first exampl for the detergent there employed, i. e., the dioctyl ester of sodium sulfosuccinlc acid, I substitute the Aquarex-D or sodium salts of sulfate mono esters of higher fatty alcohols, chiefly lauryl and myristyl derivates; or I substitute Oronite detergents which are alkyl aryl sulphonates, or, more particularly, the sodium salts of chiefly pentadecyl benzene sulfonates, hexadecyl benzene sulionates, heptadecyl benzene sulfonates, and octadecyl benzene sulionates. I also substitute the sulfonapthenates, or a product which consists chiefly of the mixture of the sodium salts of pentadecyl naphthene sulfonate, hexadecyl naphthene sulfonate, heptadecyl naphthene sulfonate, and octadecyl naphthene sulfonate. Likewise, in each of the other examples of the invention for the detergent previously specifically mentioned, I substitute any one of the specific detergents previously just specified, with the production of substantially similar products.

While in the foregoing examples I have also referred to specific rubbers, in each of the examples given there may be employed for the rubber either butadiene-acrylonitrile rubber, or polychloroprene rubber, or chloroprene-isoprene rubber, or butadiene-styrene rubber, or a rubber consisting chiefly of one of the above-mentioned synthetic rubbers with a minor proportion of natural rubber. I have specifically employed chloroprene-isoprene rubber in the examples where polychloroprene rubber is stated and found the products substantially identical to that obtained when using the polychloroprene rubber.

While the particular examples of the process and product of the present invention herein described are well adapted to carry out the objects of the invention, various modifications and changes may be made, and this invention includes all such modifications and changes which come within the scope of the appended claims.

I claim:

1. A product comprising a vulcanized synthetic rubber selected from the group consisting of butadiene-acrylonitrile rubber, polychloroprene rubber, chloroprene-isoprene rubber and butadiene-styrene rubber, having substantially homogeneously dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters, and alkyl aryl sulfonates, the detergent being present in quantities of from 10 to 80 parts per 100 parts of rubber.

2. A process of forming a rubber product capable of exuding during use a detergent, which process comprises admixing into a mass of rubber selected from the group consisting of butadieneacrylonitriie rubber, polychloroprene rubber, chloroprene-isoprene rubber and butadienestyrene rubber a vulcanizing agent and a detergent selected from the class consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates,

8 sulfosuccinic acid esters and alkyl aryl sulfonates, there being incorporated between 10 and parts of the detergent per parts of rubber, mixing said constituents, and heating and vulcanizing the mixture to produce a resilient rubber product capable of exuding such detergent.

3. A product comprising a vulcanized rubber, the rubber being chiefly synthetic rubber selected from the group consisting of butadiene-acrylonitrile rubber, polychloroprene rubber, chloropren'e-isoprene rubber and butadiene-styrene rubber, the remainder of the rubber being natural rubber, the vulcanized rubber having substantially homogeneously dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, suiiosuccinic acid esters, and alkyl aryl sulfonates, the detergent being present in quantities from 10 to 80 parts per 100 parts of rubber.

4. A process of forming a rubber product capable of exuding during use a detergent, which process comprises admixing into a mass of rubber consisting chiefly of synthetic rubber selected from the group consisting of butadiene-acrylonitrile rubber, polychloroprene rubber, chloroprene-isoprene rubber, and butadiene-styrene rubber, the remainder of the rubber being natural rubber, a vulcanizing agent and a detergent selected from the class consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters and alkyl aryl sulfonates, there being incorporated between 10 and 80 parts of the detergent per 100 parts of rubber, mixing said constituents, and heating and vulcanizing the mixture to produce a resilient rubber product capable of exuding such detergent.

5. A sponge-like, resilient rubber product capabl of exuding during use a detergent, said product comprising a vulcanized synthetic rubber selected from the group consisting of butadieneacrylonitriie rubber, polychloroprene rubber, chloroprene-isoprene rubber and butadienestyrene rubber, having substantially homogeneously dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulionaphthenates, sulfosuccinic acid esters, and alkyl aryl sulfonates, the detergent being present in quantities of from 10 to 80 parts per 100 parts of rubber.

6. A process of producing a sponge-like, resilient rubber product capable of exuding during use a detergent, which process comprises admixing into a mass of rubber selected from the group consisting of butadiene-acrylonitrile rubber, polychloroprene rubber, chloroprene-isoprene rubber and butadiene-styrene rubber, a vulcanizing agent, blowing agents. and a detergent, the detergent being selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonapth thenates, sulfosuccinic acid esters, and alkyl aryl sulfonates, there being incorporated between 10 and 80 parts of the detergent per 100 parts of rubber, mixing said constituents, and heating, blowing, and vulcanizing the mixture to produce a resilient, sponge-like, rubber product capable of exuding such detergent.

'I. A rubber product capable of exuding during use a detergent, comprising vulcanized butadieneacrylonitriie rubber, having substantially homogenecusly dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters, and alkyl aryl sulfonates, the detergent being present in quantities of from 10 to 80 parts per 100 parts of rubber. 8. A rubber product capable of exuding during use a, detergent, comprising vulcanized polychloroprene rubber, having substantially homogeneously dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters, and alkyl aryl sulfonates, the detergent being present in quant ities of from 10 to 80 parts per 100 parts of rubber.

9. A rubber produgt capable of exuding during use a detergent, comprising vulcanized chloroprene-isoprene rubber, having substantially homogeneously dispersed throughout the rubber a detergent selected from the group consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters, and alkyl aryl' sulfonates, the detergent being present in quantities of from 10 to-80 parts per 100 parts of rubber.

10. A process of forming a rubber product capable of exuding during use a detergent, which process comprises admixing into a mass of butadine-acrylonitrile rubber, a vulcanizing agent and a detergent selected from the class consisting of sulfuric acid esters of fatty alcohols. sulfonaphthenates, sulfosuccinic acid esters and alkyl aryl sulfonates, there being incorporated between 10 and 80 parts of the detergent per 100 parts of rubber, mixing said constituents; and heating and vulcanlzing the mixture to produce resilient rubber product capable of exudingsuch detergent.

rubber, mixing said constituents, and heating and vulcanizing. the mixture to produce a resilient 4 rubber product capable of exuding such detergent.

12. A process of forming a rubber product capable of exuding during use a detergent, which process comprises admixing into a mass of chloroprcne-isoprene rubber, a vulcanizing agent and a detergent selected from the class consisting of sulfuric acid esters of fatty alcohols, sulfonaphthenates, sulfosuccinic acid esters and alkyl aryl sulfonates, there being incorporated between 10 and 80 parts of the detergent per 100 parts of rubber, mixing said constituents, and' heating and vulcanizing the mixture to produce a resilient rubber product capable of exuding such detergent.

7 WILLIAM ROMAINE, JR.

No references cited. 

